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Thread: CAFS problems

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    Default CAFS problems

    My department is relatively new to Compressed Air Foam Systems. we now have 2 KME 1500 gpm pumpers with the eclipse system. as of 3/8/05
    we had the opportunity to use CAFS on a 4 plex. I personally was impressed with it's capability, However initially we had problems devoloping an effective stream. after some firehouse discussion, its was suggested that kinks in the hose line was the problem. I personally am not convinced. Can anyone suggest what might have been the problem ?


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    Suggestions

    1. type of nozzle
    2. water/air gate down one or the other
    3. throttle up


    With the proper flow the kinks will more than likely staighten out

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    We don't have that particular CAFS system, but everything I've ever read included what trsgreg said, plus depending on how often the system is used, a clogged foam strainer in the foam tank. We were told to full the tank, then put mineral oil in the top fill to cover the foam so it didn't turn into wax while exposed to the air. Seems to have worked so far.

    Nozzle selection is important, smooth bore is the normal recommendation because you don't want the fog nozzle to aerate and break up the foam stream. That strips the air out which is half of what makes the stream project well. And even though the air is adding it's energy to the system and eliminating friction loss, you still have to flow the line at the recommended nozzle pressure. So if you have 100psi nozzles, you need to have 100psi on the discharge. Smooth bore 50psi of course. We run the 50pis Sabrejets and haven't had any flow or stream issues.

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    Reinbolttw - give us some more info on what you are using - nozzle, length of hose, gated down blah blah, its hard to trouble shoot without knowing your exact situation.

    BC79er- we use a smooth bore for our caffs and it is set at 100psi, but thats air pressure - Im not familiar with the systems off of pump trucks as ours is a dedicated unit. Do you set your discharge pressure based on water or air pressure?
    -I have learned people will forget what you said,
    -People will forget what you did,
    -But people will never forget how you made them feel!

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    We have a Pierce Husky, the system matches the air pressure with the water pressure automatically. Pretty much FF proofed.

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    Have you had the training that is included with the purchase of an Eclipse yet? I would be happy to discuss training and the issue you have with you. You can e-mail me at gageske@waterousco.com, and I can either e-mail you back and or call you. I do some training for the Eclipse system and have used cafs on my department for 2+ years.
    I should be able to help you out.

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    Default Cafs problems part 2

    As for the particular of our application we are using 15/16" tip ona smooth bore nozzle an a 200'x 1 3/4" line, nozzle pressure @80 psi, utilizing a 2 to 1 air/water mix and a foam percentage of .3

    Thanks for the replies
    Please keep mthem coming
    Tom

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    Reinbolttw,

    I have to go with the kinks angle as it is a common problem, especially at such a low pump pressure. We use the same nozzle and hose set-up on our 7 CAFS engines but pump at 90 psi. We found that 80 psi only offered 75 - 85 USGPM and this was considered not enough flow. We moved up to 90 psi and achieved 90 - 105 USGPM with less kinking problems. We have found a couple of key indicators or things to watch for that may indicate kinking. Firstly you will see the flow rate on the foam head flow meter drop to approximately half, secondly, the nozzleman will notice the nozzle gets alot louder. See if you can recreate the flow problems you had and look for these two signs.

    Best of luck.

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    Default Re: Cafs problems part 2

    Originally posted by reinbolttw
    As for the particular of our application we are using 15/16" tip ona smooth bore nozzle an a 200'x 1 3/4" line, nozzle pressure @80 psi, utilizing a 2 to 1 air/water mix and a foam percentage of .3

    Thanks for the replies
    Please keep mthem coming
    Tom
    The 15/16 tip is just right for a 1 inch foresty hose, but it's like using a pea shooter barrel on cannon. Guy's open up the CAFS, get the tips off the full flow valves. Turn the pressure up to at least 110-120 psi and increase the concentrate to at least .5 because most city water is hard and .3 makes really weak, fast draining foam, if it works at all. Add a 6 foot section of hard hose before the nozzle, (like the reel tech) to keep it from kinking when the nozzleman works the hose and be sure to use the pistol grip valve 1-3/8 inch flow NOT 15/16. Use 50 gpm water flow and open the air full open because the hose limits the amount of air that will fit into the hose with 50 gallons of water flowing in it. Forget what the guys are saying about "you still need all the water", that's not right, CAFS is twenty times more efficiant than water, according to a National Institute of Standards Testing. A 15 or 20 to 1 expansion ratio is the median expansion ratio for a good CAFS discharge. That's 3 cfm to 1 gallon of water. 1 cfm equals 7.48 gallons of foam. Have the hoseman constantly checking for kinks, kinks cause serious problems by stripping the gas out of the foam and dissrupts the CAFS process. The nozzleman should get used to sounds the nozzle makes, a hissing is an idication there is a kink somewhere. Use your finger in the straight steam to cause a fan pattern in close quarters. To get a wetter foam, slightly close the nozzle to make the foam wetter but make sure it is FULL OPEN at all other times.
    Don't put oil in your concentrate tank, good grief! The foam is a surfactant, it emulsifies the oil and makes a gel. Don't use alcohol type concentrate,,,, EVER. It has poly agents in it that are not compatible with ANYTHING and are totally not necessary. All other class A's are compatible with each other and will mix with AFFF too. Ultra High Expansion is the same as Class A. Be wary of the CAFS trainer, there are very few water pump manufacturers that care about CAFS working at all.

    Just my opinion.
    Mark Cummins

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    I just took the state Foam Ops course, and I agree - get that tip off the nozzle! Wide open smooth bore, at 100 PSI. It works wonders. They showed us a bunch of tapes of controlled burns, and full involved houses went out quick, without having to go inside. Oddly, the fire died from the rear of the house toward the front.

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    WE have had good luck with our CAFS system.

    However at a car fire, the hose started "jumping" and the foam was really thin and watery. We also suspected a kink, and that will happen if the hose is kinked. But the problem was something else entirely.

    Now I'm not the most technical gal but I will try to describe how we fixed it. Try not to fall off your seat laughing:

    It turned out that the clamp around the mixing chamber/tube part had loosened off thus creating the problem. We tightened the clamp and presto: problem solved. This clamp will loosen up occasionally over our rough roads and now its a simple fix.

    Hope you had a good laugh and that the problem is this simple to fix
    IACOJ
    If you are willing to teach;
    I am willing to learn.

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    Originally posted by ROOKIELZ
    WE have had good luck with our CAFS system.

    However at a car fire, the hose started "jumping" and the foam was really thin and watery.

    First of all I want to say that I really appreciate women in the fire service,,,,, No! I realy do, because it seems women are willing to accept changes quicker than most guys I know and they realize the benefits of the light weight, easy to handle fire hose when it's filled with CAFS foam. It's fun to see the women challenge the guys with the water hoses.

    As for the "jumping fire hose" this is ALWAYS caused by not enough concentrate in the mixture. It's actually a slug of water then a slug or air, and without enough foamning agent, it's very hard to hang onto the nozzle. It's best to shut off the air when it happens and find why the mixtute is too lean. This is one of the reasons I suggest using greater than .3% setting on the concentrate meter. And don't ever let the foam tank get empty, CAFS stops working without concentrate. If your injector breaks, just dump concentrate into your booster tank and let your engineer set the partial draft into the pump if your on a hydrant or strait from the booster tank if your hauling water.
    Mark Cummins

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    Hello reinbolttw,

    My experiences with CAFS as an interior attack have been good. Both for fire knockdown and heat absorption capabilities. The key to any interior attack is to meet or exceed the critical application rate for extinguishment of the fire. CAFS is a delivery system. The extinguishment and cooling happens as a result of the water that is applied. For those who say cooling is poor with CAFS attack, I can only conclude that you are not flowing enough water (GPM). Our 1 3/4" attack lines flow approximately 100 GPM with 30-35 CFM of air, using a straight bore 15/16Ē tip. This is around the 3:1 ratio. Water is the prime ingredient. The class "A" foam makes the water more efficient and the application of the water and class "A" foam with CAFS makes it "SUPER" efficient. Whether you are using plain water or CAFS the basic principles of firefighter are still applicable, "Big Fire, Big Water" and "Put the Wet Stuff on the Red Stuff". For those who are having cooling issues with their CAFS, try a "wetter" mixture. Less air, more water.

    As far a kinking goes, no problems. We run our main pump discharge pressure at 80 to 100PSI for 1 3/4" handlines. If you run at a lower PSI, Yes, it will kink. Also I have experienced more kinking issues with rubber jacketed fire hose. The cloth jacketed fire hose lines have not given us any kinking problems.

    The statement regarding putting mineral oil on top of foam in a foam tank is ONLY APPLICABLE to class "B" foam. Do not do this with class "A" as it will break it down since it is a surfactant.

    Since you did purchase an Eclipse from Waterous, it comes with 3 days of CAFS instruction. The instructors that are hired and used by Waterous for the CAFS instruction are all firefighters that use and understand CAFS. I would contact your dealer and find out what is up with the training? 3 days of training, at your fire station comes standard with each Eclipse sold. Take advantage of it.

    Here is a link to another forum on CAFS that may help.
    http://cms.firehouse.com/forums2/sho...threadid=65806

    Be safe,

    Captain Lou
    "Got Foam?"

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    Mark Cummins wrote:

    "Be wary of the CAFS trainer, there are very few water pump manufacturers that care about CAFS working at all."

    You can be wary, but the pump manufacturers also assemble some of the CAF systems and it is a very high priority that the CAF system works. I have e-mailed reinbolttw and I believe we have addressed his issues. The only reason that I posted a reply was to add assistance if possible.

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    Questions
    On the system
    What pressure were you running the system
    What hose size including length and nozzle(tip) size
    What foam percentage type and which foam
    What I would suggest is if you have not yet received the operator instructions
    Run system at 100/120 psi
    with a 1.5/1.75" line atleast 100'smooth bore 15/16"or 1"
    Foam set at .3%
    Auto-Sync in the Run/Auto
    Open the discharge about 1/2 way to start
    Turn on the air
    Look at solution flow will probably be about 70-90 gpm
    CAF will be wet
    As you close the water/solution (discharge valve)the stream will dry out as you open wet
    If this does not work you can contact me Ray Frey 623-979-3398
    I can help
    Thank you
    Ray Frey

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    Originally posted by GreggGeske
    Mark Cummins wrote:

    "Be wary of the CAFS trainer, there are very few water pump manufacturers that care about CAFS working at all."

    You can be wary, but the pump manufacturers also assemble some of the CAF systems and it is a very high priority that the CAF system works. I have e-mailed reinbolttw and I believe we have addressed his issues. The only reason that I posted a reply was to add assistance if possible.

    Greg, I meant no offense and I apprecitate the importance of a good trainer. The problem I have been seeing with CAFS training is a confusing conflict with old water application techniques and the new ideas about how to actually use foam to fight structure fires.

    There is definately a need for a good CAFS training program based on sound facts and ligitimate information. My comment about the pump companies was intended to point out another problem with CAFS. A water pump is a pretty simple thing if that's all you have to provide on a pumper, but when you add a complex pneumatic control system and a new power transmission and all the new plumbing and hardware thats needed to integrate a LARGE air compressor into an already over-crowded compartment on a fire truck, it becomes a bad headache to offer a warranty that could hurt the company's reputation and bottom line.

    The fire departments should be buying an "ALL CAFS" truck that is NOT designed for the "what if the compressor breaks" and we need to pump water like we always were trained to do. I went to a mutual aid house fire yesterday, the fire department doesn't have a CAFS truck, and no fire hydrants available at this fire, they worked the fire as trained and did a good job, but lost the house because of poor water flow (and other excuses) overhaul took 4 more hours to cool the ashes and stop the smoke. What if they could have waved a magic wand and suddenly made the water they were using become twenty times more efficiant? And multiply it into 20 times more volume? But also make it 20 times easier to apply? Who would make the decission to not use CAFS? It's done all the time, I see CAFS trucks show up at similar structure fires and pump water. It's a training problem.

    I see LARGE CAFS systems with 15/16 tips on the nozzles and pumping 80 psi with .3% (or less) of a concentrate they don't know anything about. I see wet foam where it should have been a dry foam and I see departments that don't know how to bounce a foam stream off a back cieling to cool the CO2 in the roll-over gas's to use it to help extinguish the fire from the back of the house to the front. I ask why do they use their CAFS this way? They tell me the trainer taught them.

    Texas A&M University is just now discussing CAFS training. There are many CAFS experts that have NEVER faught a REAL structure fire with CAFS (or any other type of fire) and they are training how to use CAFS. I shouldn't name these people, but a couple of them work for well known water pump and truck manufactures. But thankfully there are a few guys that do have some real experience and are trying to provide usefull information. CAFS is still a new frontier, I learn something new everytime I use my CAFS (twenty years active duty with CAFS and I'm not an expert, YET!), I just hope the departments that spend the money are ready to learn new stuff. AND USE IT!

    just my opinion.
    Mark Cummins

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    Contact me so that we can track the status of your delivery instruction. The class will address this question and many more. Our instructors are all firefighters and CAFS users and speak from experience. You can reach me at kklassen@pneumaxcafs.com

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